The present disclosure describes a novel test boot for sealing the secondary containment of a fuel containment piping system with a split boot assembly that can be installed without disconnecting the primary piping.
Vehicle fuel is commonly conveyed from an underground storage tank to a fuel dispenser through a secondarily contained fuel pipe. The secondarily contained fuel pipe typically extends from a containment sump located above the underground storage tank to a containment sump located below the dispenser. Within either the dispenser sump or the tank sump, the secondary containment pipe is terminated in one of two ways either a closed type or an open type, as further described below. A primary/secondary piping arrangement as well as a sealing system utilized in conjunction with the same is disclosed in U.S. patent application Ser. No. 12/324,461, which published as U.S. Patent Application Publication No. 2009/0136286, entitled ENTRY BOOT, the entire disclosure of which is hereby expressly incorporated by reference herein. Other primary/secondary piping arrangements as well as sealing systems utilized in conjunction with the same are disclosed in U.S. Pat. Nos. 7,758,084 and 7,523,962, both entitled CONNECTION BETWEEN A PIPE AND A WALL, the entire disclosures of which are hereby expressly incorporated by reference herein.
Secondary containment monitoring can be of a closed type, using a termination boot to seal the end of the secondary containment area for leak detection monitoring using a VPH method. VPH monitoring is an acronym for vacuum, pressure or hydrostatic monitoring. One of these three methods is typically used to monitor the closed volume between the primary and secondary pipes with a monitoring means that will indicate to a station owner or operator a potential leak of the primary piping system. An exemplary method and apparatus for monitoring for leaks is disclosed in U.S. Pat. Nos. 7,334,456 and 7,051,579, both entitled METHOD AND APPARATUS FOR CONTINUOUSLY MONITORING INTERSTITIAL REGIONS IN GASOLINE STORAGE FACILITIES AND PIPELINES, the entire disclosures of which are hereby expressly incorporated by reference herein.
Secondary containment monitoring can also be of an open type allowing any fluid that may have leaked into the secondary containment pipe (e.g., from a leak in the primary pipe) to flow into the dispenser and/or tank sumps. A sensor located in the sump provides indication of a potential leak of the primary piping system. In this method, the ends of the secondary containment system are typically sealed on a periodic basis and verified by a service contractor to be leak tight using a VPH method.
Whether utilizing a closed or open type system for monitoring a secondary containment piping system, a boot is installed to seal off the end of the secondary containment pipe in at least certain circumstances.
Certain boot designs utilize a cylindrical, elastomeric boot that is installed onto the secondary piping system prior to the primary fitting connections being made to the ends of the piping system. Using this embodiment, one end of the elastomeric cylinder is clamped to the primary pipe and the other end clamped to the secondary pipe to seal off the secondary containment volume. While this is typically done with a cylindrical, elastomeric material, similar embodiments are also utilized. In order to replace the boot following damage or normal aging wear, the primary piping system must be disconnected in order to install a new boot.
An improvement to this method is to utilize a split boot arrangement that allows both halves of a boot to be attached on either side of the pipe and subsequently sealed to the piping system in such a way that the secondary containment area is contained.
The disclosed embodiment demonstrates a boot assembly that reliably seals the secondary containment area utilizing a split boot device that can be installed without disconnecting the primary piping. The seal includes first and second containment housings, each supporting a pair of partial ring shaped seals. The containment housings can be positioned about the primary and secondary pipes from opposing sides thereof so that disconnection of the primary pipe is not required to secure the seal in place. A clamp secures the first containment housing relative to the second containment housing in a secured position in which a first pair of partial ring seals associated with the first containment housing and a second pair of partial ring shaped seals associated with the second containment housing cooperate to form a pair of continuous ring shaped sealing surfaces including a first continuous ring shaped sealing surface including one of the first pair of partial ring shaped seals and one of the second pair of partial ring shaped seals, and a second continuous ring shaped sealing surface including a second one of the first pair of partial ring shaped seals and a second one of the second pair of partial ring shaped seals.
In one form thereof, the present disclosure provides a seal for sealing the interstitial space formed between a primary pipe and a secondary pipe positioned about the primary pipe. The seal of this form of the present disclosure includes a first containment housing supporting a first seal, the first seal comprising a first pair of partial ring shaped seals, the first pair of partial ring shaped seals each forming a partial ring. The seal of this form of the present disclosure further includes a second containment housing supporting a second seal, the second seal comprising a second pair of partial ring shaped seals. A clamp sized and shaped to secure the first containment housing relative to the second containment housing in a secured position in which the first pair of partial ring shaped seals of the first seal and the second pair of partial ring shaped seals of the second seal cooperate to form a pair of continuous ring shaped sealing surfaces comprising a first continuous ring shaped sealing surface comprising a first one of the first pair of partial ring shaped seals and a first one of the second pair of partial ring shaped seals, and a second continuous ring shaped sealing surface comprising a second one of said first pair of partial ring shaped seals and a second one of said second pair of partial ring shaped seals may be provided. In the secured position the first containment housing and the second containment housing define a containment housing longitudinal axis.
In alternative forms of the present disclosure, the first pair of partial ring shaped seals may span a first gasket and a second gasket, with the first pair of partial ring shaped seals joined by the first gasket and the second gasket. Further, the second pair of partial ring shaped seals may span a third gasket and a fourth gasket, the second pair of partial ring shaped seals joined by the third gasket and the fourth gasket. In this alternative form of the present disclosure, the clamp may sealingly engage the first gasket to the third gasket and the second gasket to the fourth gasket to form the pair of continuous ring shaped sealing surfaces.
In embodiments of the present disclosure, the first gasket may comprise a first gasket seal surface and first gasket opposite surface opposite the first gasket seal surface, the first gasket seal surface and the first gasket opposite surface forming an angle oriented so that a thickness of the first gasket increases radially inwardly toward the containment housing longitudinal axis. The second, third and fourth gaskets may share the same configuration as previously described with respect to the first gasket.
In embodiments of the present disclosure, the first continuous ring shaped sealing surface may define a first radius measured from the containment housing longitudinal axis and the second continuous ring shaped sealing surface may define a second radius measured from the containment housing longitudinal axis, with the first radius being smaller than the second radius so that the first continuous ring shaped sealing surface and the second continuous ring shaped sealing surface can simultaneously sealingly engage two different sized pipes.
In certain alternative embodiments, each of the first pair of partial ring shaped seals and/or the second pair of partial ring shaped seals may have differing thicknesses such that a thickness of such seals at a certain point is greater than a thickness of these seals at another point. The differential thicknesses may be positioned such that the increased thicknesses are positioned 180° about the containment housing longitudinal axis from each other when the first containment housing and the second containment housing are in the secured position. In certain alternative embodiments, either or both of the first and second pair of partial ring shaped seals may define an inner diameter and an outer diameter, with the inner diameter eccentric to the outer diameter to form the aforementioned differential thicknesses.
In certain forms of the present disclosure, the pairs of partial ring shaped seals may comprise O-rings, or dual lobed sealing rings presenting a pair of sealing surfaces.
In alternative forms of the present disclosure, the first and second containment housings may include external radial protrusions having opposing ramp surfaces such that a thickness of the external radial protrusions increases radially inwardly toward the containment housing longitudinal axis. In such forms of the present disclosure, a clamp comprising a pair of interior ramp surfaces complementary to said opposing surfaces of the external radial protrusions may be utilized to clamp against the opposing ramp surfaces of the exterior radial protrusions to both axially and radially align the first containment housing with the second containment housing as the clamp secures the first containment housing and the second containment housing in the secured position.
In certain forms of the present disclosure, one or both of the containment housings may include a cavity sized to receive the associated pair of partial ring shaped seals. The cavity may include a bevelled surface to accommodate an angled gasket oriented so that a thickness of the gasket increases radially inwardly toward the containment housing longitudinal axis.
One or both of the containment housings of the present disclosure may include a fitting extending from the exterior surface of the containment housing and connected in fluid communication by a channel extending through a wall of the containment housing to an interior surface of the containment housing, the channel terminating at a location intermediate the first continuous ring shaped sealing surface and the second continuous ring shaped sealing surface.
In alternative forms of the present disclosure, one or both of the containment housings may include a locator extending from an interior wall of the containment housing toward the containment housing longitudinal axis, the locator extending further inwardly toward the containment housing longitudinal axis than one of the continuous ring shaped sealing surfaces.
In alternative forms of the present disclosure, the first containment housing includes a first pair of T-shaped protrusions extending from an exterior wall of the first containment housing and the second containment housing may include a second pair of T-shaped protrusions extending from an exterior wall of the second containment housing. The seal of this form of the present disclosure may further includes a first pair of O-rings, each of the first pair of O-rings positioned about one of the first pair of T-shaped protrusions and one of the second pair of T-shaped protrusions to hingedly connect the first containment housing to the second containment housing. In alternative forms of the present disclosure, the first containment housing may include a third pair of T-shaped protrusions extending from the exterior wall of the first containment housing and the second containment housing may include a fourth pair of T-shaped protrusions extending from the exterior wall of the second containment housing. In these alternative forms of the present disclosure, the seal may further comprise a second pair of O-rings, each of the second pair of O-rings selectively positioned about one of the third pair of T-shaped protrusions and one of the fourth pair of T-shaped protrusions to selectively secure the first containment housing to the second containment housing.
In one form of the present disclosure, the seal disclosed herein may be utilized in combination with a fueling station including a primary pipe fluidly connecting an underground storage tank with a fuel dispenser and traversing an underground storage tank sump associated with the underground storage tank and a fuel dispenser sump associated with the fuel dispenser. In this form of the present disclosure, a secondary pipe providing secondary containment of the primary pipe may extend between the underground storage tank sump and the fuel dispenser sump. In this form of the present disclosure, the clamp secures the first containment housing relative to the second containment housing in the secured position so that the first continuous ring shaped sealing surface seals against the primary pipe and the second continuous ring shaped sealing surface seals against the secondary pipe.
In one form of the present disclosure, the first containment housing may extend no more than 180° about the containment housing longitudinal axis and the second containment housing may extend no more than 180° about the containment housing longitudinal axis.
In an alternative form of the present disclosure, an apparatus for conveying fluid includes a primary pipe, a secondary pipe surrounding the primary pipe and forming interstitial space therebetween and a split boot assembly. In this form of the present disclosure, the split boot assembly may include a first split boot half having an inner wall supporting a first pair of half ring seals and a second split boot having an inner wall supporting a second pair of half ring seals. The split boot assembly of this form of the present disclosure may further include a clamp engaging the first split boot half and the second split boot half to clamp the split boot assembly to the primary pipe and the secondary pipe such that the first pair of half ring seals seals against both the primary pipe and the secondary pipe and the second pair of half ring seals seals against both the primary pipe and the secondary pipe to thereby seal the interstitial space.
In certain alternative embodiments, the clamp may comprise a tapered clamp engaging a tapered outer wall of the first split boot half and a tapered outer wall of the second split boot half to align the first split boot half to the second split boot half both radially and axially when the tapered clamp clamps the split boot assembly to the primary pipe and the secondary pipe.
In certain forms of the present disclosure, the first pair of half ring seals and the second pair of half ring seals may comprise O-rings or dual lobed sealing rings comprising a pair of radially inwardly projecting sealing surfaces.
In alternative forms of the present disclosure, one or both of the first split boot half and second split boot half may include a locator extending from an interior wall of the split boot half to a radially inward position, the locator extending further inwardly than an outer diameter of the secondary pipe.
In alternative forms of the present disclosure, the first split boot half may be hingedly connected to the second split boot half. In exemplary embodiments, the first split boot half may include a pair of first split boot half T-shaped extensions and the second split boot half may include a pair of second split boot half T-shaped extensions. The apparatus of this form of the present disclosure may further include a pair of O-rings, each of the O-rings positioned about one of the pair of first split boot half T-shaped extensions and one of the pair of second split boot half T-shaped extensions to hingedly connect the first split boot half to the second split boot half.
In certain alternative embodiments, each of the first pair of half ring seals and/or the second pair of half ring seals may have different thicknesses such that a thickness of such seals at a certain point is greater than a thickness of these seals at another point. The differential thicknesses may be positioned such that the increased thicknesses are positioned 180° about a longitudinal axis of the primary pipe from each other. In certain alternative embodiments, either or both of the first pair of half ring seals and the second pair of half ring seals may define an inner diameter and an outer diameter, with the inner diameter eccentric to the outer diameter.
In alternative forms of the present disclosure, the first pair of half ring seals may span a first gasket and a second gasket, with the first pair of half ring seals joined by the first gasket and the second gasket. Further, the second pair of half ring seals may span a third gasket and a fourth gasket, the second pair of half ring seals joined by the third gasket and the fourth gasket. In this alternative form of the present disclosure, the clamp may sealingly engage the first gasket to the third gasket and the second gasket to the fourth gasket to form a pair of continuous ring shaped sealing surfaces.
In embodiments of the present disclosure, the first gasket may comprise a first gasket seal surface and a first gasket opposite surface opposite the first gasket seal surface, the first gasket seal surface and the first gasket opposite surface forming an angle oriented so that a thickness of the first gasket increases radially inwardly toward a longitudinal axis of the primary pipe. The second, third and fourth gaskets may share the same configuration as previously described with respect to the first gasket.
In certain forms of the present disclosure, one or both of the first split boot halves may include a cavity sized to receive the associated pair of half ring seals. The cavity may include a bevelled surface to accommodate an angled gasket oriented so that a thickness of the gasket increases radially inwardly toward the containment housing longitudinal axis.
The split boot assembly may further include a fitting extending from an exterior surface of the split boot assembly and connected in fluid communication by a channel through a wall of the split boot assembly to an interior surface of the split boot assembly to fluidly connect the fitting to the interstitial space formed between the primary pipe and the secondary pipe.
In a further alternative form of the present disclosure, a sealing ring includes a first gasket section, a second gasket section, and a partial ring spanning the first gasket section and the second gasket section and extending through an arc about a longitudinal axis spaced from the partial ring seal. In this form of the present disclosure, the partial ring seal includes a first radial thickness perpendicular to the longitudinal axis adjacent to the first gasket section and a second radial thickness perpendicular to the longitudinal axis and located between the first gasket section and the second gasket section, the second radial thickness being greater than the first radial thickness.
In an alternative form of the present disclosure, the second, increased thickness is midway between the first gasket section and the second gasket section. The sealing ring may further include a second partial ring seal spanning the first gasket section and the second gasket section and extending through the same arc as the first partial ring seal. In an alternative form of the present disclosure, one or both of the first gasket section and the second gasket section may include a first face and an opposing second face, with the first face diverging from the second face in a radially inward direction toward the longitudinal axis so that the first face has an increasingly greater thickness toward the longitudinal axis.
The above and other features of the present disclosure, which alone or in any combination may comprise patentable subject matter, will become apparent from the following description and the attached drawings.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the disclosure, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner.